694 CONTRIBUTIONS TO THE NATURAL HISTORY OF QUITO. 
and San Pablo Lake, it is remarkable that only one species of this 
class (so far as we can ascertain) occurs in the Quito waters. This 
is the Cyclopium Humboldtii Sw., one of the Siluride. It abounds 
in the Machangara, but we have never seen a specimen over four 
inches long. According to Dr. Gill it is generically distinct from 
the Stygogenes Humboldtii of Günther ; but we cannot distinguish 
it from the Pimelodus cyclopum mentioned by Humboldt* as in- 
* NOTE ON THE PIMELODUS CYCLOPUM OF HUMBOLDT. By F. W. Putnam. 
r James Orton, in 1870, presented to the Academy a specimen of a small Silu- 
rid which he obtained at Quito, Ecuador, and which he supposed ke the same as the — 
fish mentioned by Humboldt from the subterranean waters of the Andes. On compar- 
ing the sor with the descriptions of the species of Arges and i sp ee oa by 
Cuvier d Valenci iennes, and by Günther in kos — alight: G son 
apart ters of pre eee 
gre sing in every detail: with the short description given by Giinther of Arges brachy- 
anae pias me additional ATACE, A ies ing a short broad spine in front of the 
adip uter rays of the several fins which he men- 
rar satin 
f S. Humboldtii. 
Our specimen has the following smears which, it ea be er are taken almost 
by ach 
ft 
line distinctly marked by raised pores, and extending the whole length of the body. 
Maxillary barbles about one-half the length of the head. Anal and dorsal fins fold 
into slight grooves 
Fin formula of 
A. Cc. 
Academy specimen I+5. | 1+5+46 =13. 
A. brachycep halus, ars ; T eai : 
6. 
Günther. 
S. Humboldtii. “ 
— af LEs 
yi i 8. D. 
I+6,0. I+9. 6. 
6, [. ts | 6. 
This slight variation in the fin rays jee he the following for the three ee 
ud ctoral, 8 to 10. Ven ral, 
of the three specimens reduced to the presence or absence ae cee spine of the adipose 
dorsal, which could very easily be overlooked unless special search was made for it, 
the fin. specimen under examination, in which it was found Guus by the skin of 
th iderati Humboldt overlooked the 
spine in in his specimen, and also that it is possible that Giinther overlooked it in his 
specimens of A. brachycephalus. At all events I “eae regard its presence as of an 
generic or even specific value on the present dat 
y 
Mase ie ft * 
Pee 
Nh Pe ee r y ee ar eee” Rah Nt amy) ae 
(a ees 
